Two Korean university students have died in Cambodia's capital Phnom Penh. gettyimagesbank

By Jung Min-hoTwo Korean university students have died of an unknown cause while doing volunteer work in Cambodia, school officials said Thursday.

According to the Konyang University, the students were hospitalized in Phnom Penh Tuesday after suffering acute stomach pains.

After receiving treatment, they returned to their lodge the next day, only to start showing the same symptoms. They were immediately returned to the hospital, but one died that night and the other died early Thursday.

The cause of their deaths is still unknown.

The students reportedly did not have any medical conditions.

The university said the two, other students and professors arrived in the country on Jan. 6 to help residents build facilities and equipment. The 19-member group was scheduled to return to Korea on Jan. 19 but is planning an early return.

The school said it has notified the students' families. The parents and doctors will fly to Cambodia to look into what happened.